Additive manufacturing system, method and corresponding components for making elastomeric structures

ABSTRACT

A system for additive manufacturing a medical device, the system comprising a first dispensing system, a second dispensing system, a deposition apparatus, and a deposition substrate on a surface of which the deposition apparatus is configured to deposit at least one elastomeric material into a filament. The deposition apparatus receives the at least one elastomeric material from the first and second dispensing systems in proportions effecting a desired property in the medical device. The deposition apparatus may comprise heating and/or cooling elements, a sonic vibration module, and/or a pneumatic suck-back valve. The deposition substrate may have a configuration corresponding to a desired shape of the medical device and is configured to rotate and/or translate relative to the deposition apparatus. The system comprises a controller configured to control the deposition.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application incorporates by reference co-pending U.S. applicationSer. No. 16/680,959 entitled “MEDICAL DEVICE INCLUDING A STRUCTURE BASEDON FILAMENTS,” by the certain inventors of this disclosure and filed onNov. 12, 2019. This application also incorporates by reference U.S.provisional application No. 62/759,237, filed on Nov. 12, 2018, and62/760,030, filed on Nov. 12, 2018.

FIELD OF THE DISCLOSURE

The disclosure relates to the field of additive manufacturing, and moreparticularly to an additive manufacturing system, method, andcorresponding components for making structures based on filaments andelastomeric materials.

BACKGROUND

Additive manufacturing is an increasingly important manufacturingmethod, comprising numerous applications across many industries.Additive manufacturing, also known as “3D printing,” is regarded as atransformative method for industrial production which facilitates theproduction of a three-dimensional article from a material according to acomputer-aided design (CAD) of a definitive article by computer-aidedmanufacturing (CAM). In this sense, additive manufacturing is a digitalrevolution of analog manufacturing processes. Efforts have been made toapply additive manufacturing to articles formed from numerous types ofmaterials, including polymeric materials, a subset of which areelastomeric materials.

Additive manufacturing of elastomeric materials, including silicone, arelimited by several factors. In many existing systems, the fluidity ofthe elastomeric material requires the provision of a vat of liquidelastomeric material or precursor, in which a nozzle deposits curingagents to form a solid article from the liquid elastomeric material insitu, with leftover elastomeric material drained and washed away afterthe formation process is completed. Other additive manufacturing systemsrequire a low- or room-temperature curing or vulcanizing elastomericmaterial so that the mass of elastomeric material quickly cures and doesnot deform during the formation process, as adding multiple layers ofelastomeric material may not be accurately performed if the elastomericmaterial is uncured. Yet other additive manufacturing systems requirethat individual, discrete beads or droplets of elastomeric material areadded one at a time to build a solid three-dimensional elastomericstructure from the base up.

Existing systems for elastomeric additive manufacturing, including thosethat utilize silicone, compromise the structural quality of the finalproduct by using low viscosity, low-temperature-curing materials toenable the deposition process. It is not known in the art how to providea smooth, consistent texture of deposited material having desiredmaterial properties. In medical applications, existing additivemanufacturing systems preclude the additive manufacturing ofmedical-grade silicone, having the requisite strength, biocompatibility,and elasticity of conventionally manufactured medical products. Existingadditive manufacturing systems have therefore been unable to meet thedemand for articles made from medical-grade silicone that can exhibitthe mechanical and chemical properties obtained from existing articlesincluding medical devices formed by other, conventional manufacturingmethods such as molding and extrusion.

In healthcare applications, silicone is a desirable elastomeric materialdue to its biocompatibility and long history of implanted medicaldevices. Due to confirmatory biological testing, use of existingmedical-grade silicone materials is desirable to reduce the time fromconcept to market. Despite its accepted use in healthcare applications,silicone materials are thick and viscous and require high pressure to beinjected into molds to manufacture a precise article, such as throughinjection molding and transfer molding processes. Challenges are imposedin additive manufacturing because it is difficult to precisely extrudesignificantly viscous silicone onto a substrate into a definitive shapewith high pressure if no mold is employed, while accounting for curingand shrinkage rates, as the silicone often deforms, sags, or otherwiseloses its desired shape before curing.

While silicone materials can be processed and formed in small batches ina design phase, difficulties arise when scaling up production ofsilicone as not only is its viscosity difficult to manage, but otherfactors must be considered including curing temperature and time,entrapment of air or bubbles, shrinkage, mixture of parts, andcross-linking to manufacture medically-accepted articles. Silicone is athermoset polymeric material and will cure into its given shape of astrong, dimensionally stable and heat- and chemical-resistant article,but such advantages also require that the structure into which thesilicone cures must be made correctly at the onset as later adaptationis typically not feasible. This limits the customizability ofelastomeric structures formed through additive manufacturing. Anyadditive manufacturing process on a commercially scalable level shouldbe able to preserve the mechanical properties of a cured silicone, suchas toughness and elasticity and other properties desirable in amedical-grade silicone article while offering high throughput andprecision.

Existing systems for additive manufacturing may provide for only amonolithic or single-property structure, as only a single grade or blendof material can be deposited. The structures and functions ofadditive-manufactured articles are limited to what can be achievedthrough a single material property. There is a need for an additivemanufacturing system that can accurately deposit material havingdifferent properties to attain a final product with desired propertiesin desired regions.

Another problem of existing manufacturing systems is that many arelimited to depositing a single discrete bead of elastomeric material ata time, limiting the construction of 3D-printed articles todiscontinuous structures that are a sum of individual drops or beads,rather than comprising smooth and continuous layers, filaments, orstructures with varying properties.

Many production and manufacturing methods are limited to providing amold in which elastomeric material may be injected and thereafter curedto attain a desired shape and properties. This considerably limits thedesign and manufacturing flexibility when preparing an article. Becauseexisting methods are limited to processes that deposit discrete beads orinject elastomeric material into negative molds, there is a need for asystem that can deposit filaments of elastomeric material to form astructure with desired properties at desired locations.

Existing systems are directed to implementations where an article isbuilt from the bottom up and only in cartesian coordinates. In othersystems, the effects of gravity on uncured or partially cured polymermaterials limit the dimensions of the article, as too much materialadded to the article causes distortions from gravity, particularlycombined with the effects of viscosity and curing rates as discussedabove. There is a need for an additive manufacturing system thatovercomes the effects of gravity and allows for additive manufacturingof articles in multiple dimensions.

Solutions that attempt to perform additive manufacturing on a rotatingbuild surface or substrate do not provide for the additive manufacturingof medical-grade silicones, which require particular viscosities andcure rates, but rather as limited to systems that utilize shavers orcutters that remove extra, unwanted deposited material. These systemsalso are configured to allow material to drip or fall away from thesubstrate. There is no teaching of using a rotating substrate thatachieves desired printing of medical-grade structures from siliconewithout cutters and dripping configurations to conductive negativemanufacturing procedures.

There is a need for an additive manufacturing system that overcomes thelimitations of existing systems, namely that low-quality elastomericmaterials are used to enable deposition limited to depositing discretebeads, that properties of materials are monolithic and cannot be dynamicto account for different structural and functional needs at differentparts or components of an elastomeric additive-manufactured article, andthat the methods for additive manufacturing are limited to bottom-upapproaches, with gravity effects unmitigated and unaddressed. It ishighly desirable to use known silicone materials having confirmatorybiological testing in additive manufacturing to create precisesilicone-based structures suitable for medical devices.

SUMMARY

The additive manufacturing system, method and corresponding componentsfor making silicone structures of the disclosure advantageously providesa system for providing material in desired quantities and at desiredlocations of an article with an improved dispensing and depositionapparatus, resulting in smooth, continuous depositions of beads,filaments, or layers of material with controlled variation of desiredproperties and at desired locations. The additive manufacturing systemof the disclosure may comprise three primary dispensing systems,including a first dispensing system, a secondary dispensing system, anda deposition apparatus. The additive manufacturing system may furthercomprise a deposition substrate arranged to cooperate with the threeprimary dispensing systems.

The first dispensing system may comprise a vat or reservoir of at leastone additive manufacturing material, the material arranged to be drawnfrom the vat or reservoir, and transmitted to the secondary dispensingsystem as the additive manufacturing system forms an article from thematerial. A separate vat or reservoir may correspond to differentmaterials. Silicone is often of a two-part, 1:1 mix ratio materialpreferably drawn from at least two reservoirs, although more reservoirsmay create different combinations of silicone compositions with desiredproperties at desired locations of an additively manufactured article.

A secondary dispensing system may comprise a proportioning column ordevice and control valves arranged to correspond to or cooperate withthe respective vat or reservoir of the first dispensing system. Theproportioning column preferably draws the material from the reservoirand stores it in a volume of the proportioning column. The controlvalves associated with the proportioning column are arranged to controla rate and volume according to which the material is stored in theproportioning column and at which it may be transmitted towards thedeposition apparatus. A plurality of proportioning columns andcorresponding control valves may be provided and may each correspond toa respective vat or reservoir in the first dispensing system, with eachof the proportioning columns, control valves, and vats containingdifferent materials or blends of materials selected and proportioned toimpart desired properties to the final article.

The deposition apparatus is arranged to receive the material from theproportioning column in rates and volumes that correspond to propertiesdesired at specific locations along with an article being formed. Thedeposition apparatus comprises a dynamic mixer to blend the material,which as discussed may comprise two or more components or separate partsblended before being deposited.

The deposition apparatus may have a modular construction and compriseheat transfer components, sonic vibration components, pneumatic stopvalves, and other modules as may enable a smooth, consistent depositionof the material while varying desired properties. A nozzle may beprovided for depositing the material onto the article.

A deposition substrate may be arranged to cooperate with the additivemanufacturing system. The deposition substrate may comprise a movingsubstrate on which the material may be deposited and cured. The movingsubstrate may counteract or overcome the effects of gravity on thedeposited material, thereby keeping it in a desired dimensional state asit cures. The deposition substrate allows for forming an article withdesired features and properties in desired locations in different pathsor orders than are available in existing additive manufacturing systems,particularly for materials like medical-grade silicone. The depositionsubstrate may comprise heat transfer components for tailoring the curerate of the deposited material and improving the process of depositionas the material may better retain a desired shape and configuration.

These and other features of the present disclosure will become betterunderstood regarding the following description, appended claims, andaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an additive manufacturing systemaccording to an embodiment.

FIG. 2 is a perspective view of a secondary dispensing system of theadditive manufacturing system of FIG. 1.

FIG. 3 is an elevational view of a deposition apparatus of the additivemanufacturing system of FIG. 1.

FIG. 4 is a cutaway elevational view of a material flow portion of theadditive manufacturing system of FIG. 1.

FIG. 5A is a perspective view of a deposition apparatus of the additivemanufacturing system of FIG. 1.

FIG. 5B is an elevational cross-sectional view of the depositionapparatus of FIG. 5A taken along the line VB-VB.

FIG. 6 is a perspective cutaway view of the deposition apparatus of FIG.5A.

FIG. 7A is a cutaway detail view VIIA of the pneumatic valve assembly ofthe deposition apparatus of FIG. 5A.

FIG. 7B is a cutaway elevational view of a heat transfer system in anembodiment of a deposition apparatus of an additive manufacturing systemaccording to the disclosure.

FIG. 8 is a cutaway perspective view of a coextrusion depositionapparatus comprising parallel dynamic mixing apparatuses according to anembodiment of an additive manufacturing system according to thedisclosure.

FIG. 9 is an elevational view of a deposition apparatus and a depositionsubstrate according to an embodiment of an additive manufacturing systemaccording to the disclosure.

FIG. 10 is a plan view of the deposition apparatus and depositionsubstrate of FIG. 9.

FIG. 11 is an elevational cutaway view of a deposition apparatusaccording to an embodiment of an additive manufacturing system accordingto the disclosure.

FIG. 12A is a plan view of a deposition substrate according to theadditive manufacturing system of FIG. 9.

FIG. 12B is a cutaway elevational view of the deposition substrate ofFIG. 12A.

FIG. 12C is an elevational view of the deposition substrate of FIG. 12Aaccording to an embodiment.

FIG. 13A is a perspective view of a nozzle of a deposition apparatusaccording to an embodiment.

FIG. 13B is a perspective view of the nozzle of FIG. 13A and adeposition substrate according to an embodiment.

FIGS. 14A and 14B are perspective views of a mounting mechanismaccording to an embodiment of the disclosure.

FIG. 14C is a perspective view of a mounting mechanism and a depositionsubstrate according to an embodiment of the disclosure.

The drawing figures are not necessarily drawn to scale, but instead aredrawn to provide a better understanding of the components, and are notintended to be limiting in scope, but to provide exemplaryillustrations. The figures illustrate exemplary configurations of anadditive manufacturing system, and in no way limit the structures orconfigurations of the additive manufacturing system, methods, andcorresponding components according to the present disclosure.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

The additive manufacturing system, method, and corresponding componentsfor making elastomeric structures of the disclosure address thelimitations of existing additive manufacturing systems by providing afirst dispensing system, a secondary dispensing system, and a depositionapparatus according to embodiments of the disclosure. The additivemanufacturing system achieves controlled variability of materialproperties throughout a produced article, with a dynamic mixingapparatus that creates smooth, consistent material blends for precise,discrete and/or continuous deposits of material such as filaments ofelastomeric material that chemically bond together to define anelastomeric 3D-printed article. A dynamic deposition substrate may bearranged for cooperating with the deposition apparatus to overcome theeffects of gravity and to facilitate dynamic orders or paths of additivemanufacturing. Combinations of these components may be provided withother known components, and do not have to be used in combination withone another.

Structures that can be manufactured according to the system, methods,and components thereof are described in co-pending U.S. application Ser.No. ______ entitled “MEDICAL DEVICE INCLUDING A STRUCTURE BASED ONFILAMENTS,” by certain inventors of this disclosure, and concurrentlyfiled on Nov. 12, 2019.

The Applicant incorporates herein by reference the “6^(th) EditionSilicone Design Manual by Albright Technologies Inc.,” atwww.Albright1.com, and retrieved on Nov. 8, 2018, published by AlbrightTechnologies of Leominster, Mass., U.S.A.

FIG. 1 depicts in perspective view an additive manufacturing system 100according to an embodiment of the disclosure. A first dispensing system102 comprises vats or reservoirs containing at least one material and isconnected to a secondary dispensing system 104, which provides materialfrom the first dispensing system 102 to a deposition apparatus 106 indesired proportions. The additive manufacturing system 100 may bearranged to cooperate with a deposition substrate 130, as will bedescribed further herein.

Examples of medical-grade elastomer that may be utilized by the additivemanufacturing system 100 include silicone, polyurethane, or otherelastomeric materials. For the disclosure, the embodiments will bedescribed as formed from medical-grade silicone. An example of amedical-grade silicone is obtainable from NuSil Technology ofCarpinteria, Calif., under product designations MED-4901, MED-6340, orMED-6345, although other silicone compositions can be used.

FIG. 2 is a perspective view of a secondary dispensing system 104, asshown in the embodiment of FIG. 1. The secondary dispensing system 104comprises a plurality of proportioning columns or devices 112A, 112B,112C, 112D. Each of the proportioning columns 112A, 112B, 112C, 112D isconnected to a corresponding vat or reservoir in the first dispensingsystem 102 via a respective reservoir feed line 108A, 108B, 108C, 108D.Elastomeric material, additives, pigments, crosslinking agents, curingagents, or any other suitable component may be provided from thereservoirs in the first dispensing system 102 to the secondarydispensing system 104 via the reservoir feed lines 108A, 108B, 108C,108D. In embodiments, the elastomeric material may be liquid siliconematerial comprising two parts, which may be cured to form a solidsilicone structure.

The proportioning columns 112A, 112B, 112C, 112D may be configured toreceive within an interior volume thereof (not shown) a quantity ofmaterial or other material from the vats or reservoirs in the firstdispensing system 102, and to distribute the material via respectiveproportioning control valves 114A, 114B, 114C, 114D toward thedeposition apparatus 106. The proportioning columns 112A, 112B, 112C,112D may draw the material from the vats in the first dispensing system102 in a controlled manner via receiving control valves 110A, 110B,110C, 110D. The receiving control valves 110A, 110B, 110C, 110D arearranged to maintain a specified volume of material in the proportioningcolumns 112A, 112B, 112C, 112D and/or to provide a required amount ofmaterial based on the deposition process downstream of the proportioningcolumns 112A, 112B, 112C, 112D.

The receiving control valves 110A, 110B, 110C, 110D may beservo-controlled or otherwise controlled, and are arranged tocommunicate with a controller. The controller may comprise amathematical model and/or a process control scheme to direct thereceiving control valves 110A-D and the proportioning control valves114A, 114B, 114C, 114D to open and transmit the material in the interiorvolume of the proportioning columns or devices 112A, 112B, 112C, 112D tothe deposition apparatus 106 in desired proportions to effect desiredproperties at desired locations in the article.

By providing the controller in communication with the proportioningcontrol valves 114A, 114B, 114C, 114D, desired amounts of materialtypes, including the two parts of a liquid silicone material, or otheradditives, may be provided at specific times corresponding to a momentduring a deposition process at which the deposition apparatus 106 willdeposit the material or additives at a desired location on the formedarticle. As the proportioning columns 112A, 112B, 112C, 112D, andrespective proportioning control valves 114A, 114B, 114C, 114D actsimultaneously and cooperatively, infinitely many combinations of thetwo parts of the liquid silicone material and other additives may bedefined, providing the formed article with precise combinations ofmaterial to form continuous sections, features, and components havingdesired properties and without interruption to the flow of the materialthrough system 100, as opposed to the monolithic articles formed byexisting methods of additive manufacturing or by methods such asinjection molding, which have unvarying properties throughout thearticles.

For example, the secondary dispensing system 104 may be arranged tocreate material blends comprising elastomeric polymeric materials, suchas parts A and B of a two-part silicone material mix, and additives thatmay influence the cure times of the material blend, the cure temperatureof the material blend, color, stiffness, strength, elasticity, or anyother property of particular regions of the final article. The secondarydispensing system 104 advantageously may provide elastomeric materialsand additives in any proportions needed, so infinitely many combinationsof properties may be attained and at desired locations along with thearticle.

While in the embodiment of FIG. 2, only four proportioning columns 112A,112B, 112C, 112D are depicted, it will be appreciated that fewer or moreproportioning columns may be utilized as deemed suitable. For example,in large or complex articles, more proportioning columns may be providedto supply additional specialized additives or different types ofpolymeric materials. For example, silicone oils may be provided foradjusting a durometer of certain materials, accelerators may be providedto adjust cure times, and other agents or additives may be provided forfine-tuning the properties of the final materials in the article.Redundant vats or proportioning columns may be provided to facilitatecontinuous deposition of the article when a particular vat orproportioning column runs out of a material part.

FIG. 3 is an elevational view of a deposition apparatus 106 according tothe embodiment of the additive manufacturing system 100 introduced inFIG. 1. The deposition apparatus 106 may comprise a deposition head 120and a feed component 122, the deposition head 120 controlling thedeposition of material onto an article, and the feed component 122controlling a rate and quantity at which material is fed from thesecondary dispensing system 104 to the deposition head 120. The feedcomponent 122 may comprise a material inlet 123 configured to receivematerial at or from the proportioning control valves 114A, 114B, 114C,114D. The feed component 122 may be mounted on a rack 130 relative tothe deposition head 120, facilitating movement of a displacement pump124 to conduct material towards the deposition head 120. An actuator 140may be arranged to translate the displacement pump 124 or to translatethe deposition head 120 in the desired direction. A nozzle 190 depositsthe material onto an article being formed.

Material is configured to be received from the secondary dispensingsystem 104 at a displacement pump head 125 via a displacement pumpcontrol valve 126. The displacement pump 124 ultimately conducts thematerial from the displacement pump head 125 towards the deposition head120. The control valve 126 advantageously is configured to conduct thematerial in a first-in, first-out manner; that is, the material is movedto the deposition head 120 in the order in which it was conducted fromthe secondary dispensing system 104, retaining its properties andsequential order of dispense. This allows the properties of the printedarticle to be controlled all the way back to the receiving controlvalves 110A-D and the respective reservoirs of the primary dispensingsystem 102, improving the particularity of the control of the processand the efficiency of resource consumption.

The displacement pump 124 may comprise a piston pump, with an outercomponent and an inner component concentric with, the interior of,and/or adjacent to the outer component. As seen in greater detail in thecutaway elevational view of FIG. 4, material may flow or be conductedfrom the secondary dispensing system 104 in a flow direction 136 infirst and second material inlets 131A, 131B, corresponding respectivelyto parts A and B of an uncured or unpolymerized elastomeric material, inan exemplary embodiment a two-part silicone material. The material isconducted in the separate first and second material inlets 131A, 131B tofacilitate fluid flow uninterrupted by formation of elastomer solids.The actuator 126 is arranged to conduct the material in a first-in,first-out manner through the displacement pump head 125 into a materialfill port 132 arranged at the inner component of the displacement pump124.

As the material accumulates through the material fill port 132 in theinner component of the displacement pump 124, piston rods 135 are guidedbackward in a direction 137 towards the displacement pump head 125. Thepiston rods 135 are configured to receive accumulated material in aninterior volume thereof without blending or otherwise affecting theorder of the accumulated material. As the piston rods 135 are drivenoutward toward the deposition head 120, the accumulated material isconducted toward the deposition head 120 in the same order in which itwas received at the displacement pump 124 from the secondary dispensingsystem 104, such that materials having desired properties will bedeposited at the desired locations on the article.

The displacement pump 124 conducts the material towards the depositionhead 120 of the deposition apparatus 106. As seen in FIGS. 5A and 5B,the deposition head 120 may comprise a dynamic mixing module 150configured to both actuate and blend the material, such as parts A and Bof two-part silicone material, preparatory to depositing the blendedmaterial on the substrate to form the article. The deposition head 120may further comprise a heat transfer module 160, which facilitatesheating or cooling of a block forming the deposition head 120. Apneumatic suck-back or stop valve 162 is provided proximate a nozzle 190to achieve a clean cut-off of blended material after a discrete portionof material has been deposited on the article.

In embodiments, the pneumatic suck-back valve 162 may be arranged todefine distinct filaments of a plurality of filaments that together forma 3D-printed article. As the deposition head 120 deposits material atdifferent portions of an article, the pneumatic suck-back valve 162 maybe actuated to retract or withdraw the material in the deposition headaway from the nozzle 190 to facilitate a clean break between thedistinct filaments or portions of the article. The deposition therebyavoids the problem of strings of material forming or smearing throughoutthe article. Whereas existing printheads reverse a flow direction of thematerial to enact a suck-back by reversing a rotation of an impeller, asdiscussed in greater detail below, the pneumatic suck-back valve 162 ofembodiments of the disclosure utilizes instead a piston arrangement thatcreates a vacuum effect to withdraw as desired the material away fromthe nozzle, creating clean breaks to distinguish individual filaments,beads, or layers of printed material.

Additional mixer or valve modules may be advantageously added to thedeposition head 120 as desired. For instance, a sonic vibration module164 is provided proximate the nozzle 190 to provide an additionalblending procedure, for example, to reduce a viscosity of the blendedmaterial and/or to activate certain additives in the material. Thedeposition apparatus 106 may advantageously be configured as a modularassembly to be easily dissembled and reassembled for easy cleaningand/or for interchange of individual components based on the needs of aparticular task. Where additional vibration, heat transfer, or suck-backmodules are required, for example, such may be easily added to and laterremoved from the deposition head 120.

Scorelines may be provided at grooves and/or between individual modulesin the deposition apparatus 106, or anywhere along with the additivemanufacturing system 100, where leakage of material from inside theadditive manufacturing system 100 is encouraged, the leakagefacilitating the expulsion of contaminants from the material. This maybe utilized especially in high-purity applications such as producingmedical-grade silicones, where contaminants are unsuitable for use withthe human body.

Turning to FIG. 5B, the dynamic mixing module 150 may comprise animpeller 180 configured to dynamically mix material obtained from firstand second control valves 170A, 170B, the first and second controlvalves 170A, 170B arranged to conduct and dispense material from thedisplacement pump 124 according to a desired final blend of material. Acontrol valve actuator 175 may be arranged to communicate with thecontroller and to independently actuate the first and second controlvalves 170A, 170B based on the desired material property at a desiredlocation along the article. The first and second control valves 170A,170B may correspond to parts A and B of a two-part silicone material orotherwise can correspond to respective proportioning devices of thesecondary dispensing system 104.

The cutaway perspective view of the deposition apparatus 106 shown inFIG. 6 illustrates the operation of the deposition head 120 on receivedmaterial. As the material is obtained from an interior volume 133 of thedisplacement pump 124, the control valves 170A, 170B control the rateand volume at which the material, in this embodiment provided in twoparts A and B, may advance toward the dynamic mixing module 150. Asmaterial part A passes the control valve 170A, it is conducted along aflow direction 171 toward the material part B provided from the controlvalve 170B, and then both parts A and B may advance in a combined butunblended flow at a flow direction 172 toward the dynamic mixing module150.

The impeller 180 is driven by an actuator 151 to rotate in a directionR1, with protrusions 182 actuating downward flow of the combined butunblended material parts A and B. As parts A and B flow through dynamicflow paths 183 defined by and between the protrusions 182, parts A and Bare blended to obtain a smooth and consistent material mixture. In anexemplary embodiment, the dynamic mixing module 150 advantageouslyremoves air bubbles from the material, facilitating a more structurallysolid, smooth, and aesthetically pleasing formed article. The generallydownward flow paths 183 thus conduct the material in a flow direction173 towards the nozzle 190. The impeller 180 further is arranged to keepthe pressure constant, which improves flow and consistency.

As the blended material passes by a distal end of the impeller 180, theblended material passes along a flow direction 174 toward the nozzle190. A sonic vibration module 164 may provide additional blending andmay advantageously reduce the viscosity of the blended materialimmediately prior to deposition when desired, for example to increase anamount of material deposited at a particular location. In embodiments,certain additives contained in the blended material may be arranged toactivate or change properties upon receiving sonic vibrations at thesonic vibration module 164, thereby enhancing properties of the blendedmaterial immediately before deposition.

The pneumatic suck-back or stop valve 162, as seen more clearly in thecutaway elevational view of FIG. 7A provides a clean cut-off of theblended material, operating to temporarily arrest the flow of theblended material along the flow path 174 by providing a negativepressure that draws blended material back up a distance in the flowchannel 184, thereby preventing unwanted deposition, smearing, ordripping of blended material from the nozzle 190. As discussed, this maybe particularly advantageous when defining distinct filaments ofmaterial and/or at distinct points on the printed article.

The pneumatic suck-back valve 162 comprises a plunger 163 configured byoperation of a driver to sharply withdraw away from the flow channel184, creating a negative pressure in a pneumatic stop line 166 thatdraws the blended material back upwardly from the nozzle 190, towardwhich the blended material otherwise flows due to the actuation of theimpeller 180 and in certain configurations due to gravity and backpressure applied from the displacement pump 124. The negative pressurecan be released as the plunger 163 is released by the driver and allowedto return to its original configuration, and the flow of the blendedmaterial along the flow path 174 is reestablished.

The arrangement of the pneumatic suck-back valve 162 with the plunger163 facilitates retraction of material and clean breaks between distinctdrops, filaments, or layers without requiring that the actuator 151reverse its rotation in order to create the retraction. Whereas existingprintheads utilize reverse-flow to retract material, the operation ofthe dynamic mixing module 150 is simplified, and wear and tear on theactuator 151, and the impeller 180 are minimized, by the provision ofthe modular pneumatic suck-back valve 162.

In embodiments, the pneumatic suck-back valve 162 can operate to defineapertures in a layer, film, filament, or other deposit of material withhigh precision. As the deposition apparatus 106 lays down or deposits anotherwise continuous layer or filament of material, the pneumaticsuck-back valve 162 may interrupt the deposition for a controlled amountof time to define a gap or aperture in the continuous layer or filament.

The pneumatic suck-back valve 162 may be particularly active andadvantageous during stages of deposition where the deposition head 120is changing a direction along the substrate. For example, the depositionhead 120 and the substrate may be arranged to move relative to eachother such that the deposition head 120 and the nozzle 190 travel alonga surface of the substrate and deposit a continuous filament thereonwhile additively manufacturing the article. As the deposition head 120so travels and deposits the continuous filament, the deposition head 120and the substrate may change a direction of travel, defining an edge orcorner portion of the article, or otherwise defining a break in acontinuous filament. The pneumatic suck-back valve 162 may, at themoment that the direction of travel is changed, activate to retract thematerial flowing through the flow path 174 to effect a clean breakdistinguishing the filament or material deposited along the surface ofthe substrate. The pneumatic suck-back valve 162, as depicted anddescribed is merely exemplary, and other suitable methods, components,and arrangements are envisioned for providing a clean cut-off ofmaterial at the nozzle 190.

The nozzle 190 may comprise any configuration or size for varied andcontrolled deposition of material. In certain embodiments, the nozzle190 may have a larger diameter configured to deposit discrete beads orcontinuous layers of material, while in other embodiments, the nozzle190 may have a nozzle configured for depositing a continuous filament.The nozzle 190 may have a circular diameter or may comprise a texturedaperture allowing for depositions of beads, layers, or filaments havingdesired textural features. The nozzle 190 may have a dynamic size and/orshape, and can change during deposition to form different sized andshaped deposits. In embodiments, the nozzle 190 may be sized to allowfor concentric or coaxial arrangements and flows of different materials,as described in greater detail below.

In embodiments, the nozzle 190 has a same size throughout the course ofadditively manufacturing a single article. The thread diameters of thelayers and/or filaments deposited by the nozzle 190 can be adjusted bycontrolling the proportions of the print speed, i.e. the flow rate ofthe material through the deposition head 120, and the material dispenserate, i.e. the flow rate of material from and through the first andsecond dispensing systems 102, 104. This allows for variable thicknessesand stiffnesses throughout the printed article while continuing thecontinuous print layers from a single size nozzle 190.

FIG. 7B illustrates the operation of the heat transfer module 160. Aheat transfer medium or fluid is conducted through at least one heattransfer line 164 along a flow path 166 within a block 155, defining atleast partially the deposition head 120. The block 155 may be formedfrom aluminum, stainless steel, Teflon, polymers, or any other suitablematerial that provides sufficient mechanical support, material purity,and/or heat-transfer characteristics. The material forming the block 155may advantageously be chosen for minimizing contamination of thematerial flowing therethrough, this arrangement facilitating the use andproduction of medical-grade elastomeric articles.

In certain embodiments, the heat transfer fluid may be a refrigerant orother cooling fluid such as cooling water arranged to reduce atemperature of the block 155 and consequently of the material flowingthrough flow channels 171, 172, 173, 174 defined therein. This may beparticularly advantageous for low temperature-curing materials, thecooling effects preventing premature polymerization. In otherembodiments, the heat transfer medium may be arranged to add heat to theblock 155, for example, to increase a property such as viscosity of thematerial flowing through the block 155.

The heat-transfer module 160 may be controlled manually or by thecontroller based on information obtained through temperature and/orpressure sensors arranged throughout the deposition apparatus 106. Forexample, a downstream temperature of the blended material exiting thedynamic mixing module 150 may trigger, based on a process control schemeaccording to the calculated properties of the blended material, a needfor temperature reduction in the block 155. The heat-transfer module 160may communicate with the controller to automatically increase a flowrate of a cooling fluid to decrease the temperature of the block 155,and consequently of the blended material exiting the dynamic mixingmodule 150.

In embodiments, the controller may indicate or determine that atemperature in the block 155 should be increased to, for example,increase temperature and decrease viscosity of the material. This may bebeneficial when the flowrate and deposition rate needs to be increasedat a particular location for increased thickness or rigidity ofparticular filaments or segments. In embodiments where the heat-transfermodule 160 is a cooling module, the flowrate of cooling heat-transferfluid or medium (such as cooling water) may be correspondinglydecreased; conversely, when the heat-transfer module 160 is a heatingmodule, the flowrate of heating fluid or power may be correspondinglyincreased.

When arranged as a heating module, the heat-transfer module 160 mayutilize any suitable heating element, including heated fluids arrangedto flow through the at least one heat-transfer line 164, electricheating elements arranged to extend through a thickness of the block155, or any other suitable arrangement or component. The heat-transfermodule 160 may be arranged to transfer heat from discrete portions ofthe block 155 or any portion of the deposition head 120 at differenttimes; for example, the heat-transfer module 160 may provide headupstream of and proximate the impeller 180 while removing heat proximatethe nozzle 190. In other embodiments, the heat-transfer module 160 mayremove heat proximate the impeller 180 to prevent any undesired curingin the deposition head 120. The heat transfer performed by theheat-transfer module 160 may be dynamic and can vary based on thecomposition of the material flowing through the deposition head 120 atany given time.

Likewise, the pressure of the material may be monitored via pressuresensors at any number of locations in the additive manufacturing system100. The controller may be arranged to detect a pressure at an outletof, for example, the dynamic mixing module 150, the displacement pump124, or the nozzle 190, with adjustments made at the displacement pump124, the control valves 170A, 170B, and/or the control valves 114A,114B, 114C, 114D of the secondary dispensing system, for example, tomaintain a proper pressure of the material throughout the additivemanufacturing system 100 and to optimize the flow characteristics of thematerial.

In an alternative embodiment of the additive manufacturing system 100shown in FIG. 8, a deposition apparatus 206 is arranged for coextrusionof material blends having different and discrete properties. Multipledynamic mixing modules, receiving material having different properties,are arranged in parallel. For instance, a first dynamic mixing module210 may comprise an impeller 281 housed within a block 211, blending andactuating a first material in a flow direction 271 towards a nozzle 290.

A second dynamic mixing module 220 comprises a second impeller 282housed with a second block 222 and blends and actuates a second materialin a flow direction 261 towards the nozzle 290. As in the depositionapparatus 106 described previously, the impellers 281, 282 blendelastomeric materials, including, for example, two-part siliconematerials and may provide a dynamic mixing of the two material parts tocreate a smooth, consistent material blend. Each dynamic mixing module210, 220 may combine and blend first and second parts A, B of separatesilicone materials.

The blended materials from the impellers 281, 282 are directed in secondrespective flow directions 272, 262 towards a coextrusion flange 250.The coextrusion flange 250 is arranged to have multiple layers with aconcentric or coaxial relationship, but in other embodiments may haveany suitable configuration of layers and shapes. As the blendedmaterials are conducted through the coextrusion flange 250, thecoextrusion flange 250 directs the blended materials in a thirdrespective flow direction 273, 263.

The coextrusion flange 250 may comprise a flange defining a centralaperture and an outer aperture, the outer aperture concentric with thecentral aperture and separated by a flange wall. The material from thesecond dynamic mixing module 220 may be directed through the outeraperture as the material from the first dynamic mixing module 210 isdirected through the inner aperture, for example.

At a distal or nozzle-facing end of the coextrusion flange 250, thefirst and second blended materials having different properties areconducted into a combination chamber 251, in which the blended materialsare no longer separated by the flange wall but rather are combined in aconcentric and laminar relationship. Because the first and secondblended materials are pre-blended when they are arranged in and passthrough the combination chamber 251, no blending of the two blendedmaterials is necessary, but rather the blended materials—one forming anouter layer and one forming an inner concentric layer, for example—mayabut each other and consequently chemically bond to each other aftercuring, while retaining distinct material properties.

In an embodiment, the first blended material forming the inner layer maybe a low-temperature-curing elastomeric material, arranged to cure andsolidify rapidly upon deposition. By contrast, the outer layer may be ahigh-temperature-curing elastomeric material, arranged to cure moreslowly upon deposition, so the outer layer may form chemical bonds dueto its uncured state with adjacent and subsequently deposited features.This arrangement allows for a bulk of a deposited material, which may bea continuous filament, to be quickly cured such that smearing isminimized, but allowing for sufficient bonding between adjacentfilaments to occur for the mechanical strength of the formed article.

After the blended materials have been combined but not blended in thecombination chamber 251, the combined material is conveyed alongrespective coaxial flow paths 274, 264 towards the nozzle 290, where thecombined material, owing to the smooth consistency afforded by thedynamic mixing at the impellers 281, 282, may be deposited as continuousfilaments, discrete points or dots, or as continuous films or layers inan additively manufactured article.

As the additively manufactured article is formed layer by layer,filament by filament, drop by drop, or by combinations of differentdeposition patterns, the properties of the materials may be dynamicallychanged, such that a first region of the article may comprise a certaindurometer, elasticity, mechanical strength, color, curing rate, and/orother property, while subsequently deposited regions may comprisedifferent durometers, elasticities, mechanical strengths, colors, curingrates, and/or other properties, while being continuously additivelymanufactured. This arrangement is made possible by the dynamic mixingcapabilities of the deposition apparatus 206 and the precision blendingof particular materials afforded by the first and secondary dispensingsystems and displacement pump as described above, which conducts thematerials to the deposition apparatus 206 without necessarily blendingthe different materials.

For details on the structure provided by the system, method, andcomponents thereof, reference is made to the aforementioned co-pendingapplication Ser. No. ______, which describes discretely and continuouslydeposited filaments of elastomeric material. The deposited material isdescribed in the preferred embodiment of a plurality of filaments thatmay abut and are adjacent in x-, y- and z-coordinates/planes to form adefinitive article. The filaments are deposited in an uncured or atleast partially cured state while retaining the deposited shape. Thenozzle and thus the filaments may be adapted for minute filaments ordeposited material, such as a 0.1 mm diameter, or other shapes andsizes. In embodiments, nozzles of different shapes and diameters may beprovided having any number of different arrangements of shapes, sizes,and concentric or axially arranged layers of material.

While the depicted embodiment describes a system wherein two parallelsystems merge to form a combined material having discrete layers withdifferent properties, it will be appreciated that any number of parallelsystems may be provided to form combinations of materials having anynumber of properties. For example, a combined material may be formedfrom two parallel systems and arranged to have a laminar arrangement,with two sheets of combined but unblended materials, which may befurther arranged with and attached to filaments having discrete innerand outer layers formed in another pair of parallel systems.

The parallel systems may be arranged, in certain embodiments, to provideblended material to the coextrusion flange 250 or the combinationchamber 251 dynamically. In embodiments, a first parallel system maydeliver a first blended material as an inner layer of a continuousfilament and a second parallel system may deliver a second blendedmaterial as an outer layer of the continuous filament as describedabove, while a third parallel system may deliver a third blendedmaterial to the second blended material in the outer layer according toa dynamic pattern. For example, at times the third blended material maybe added and can be mixed to the desired degree with the second blendedmaterial as suitable for a resulting property at a particular locationon the additively manufactured article, and at other or subsequent timesthe flow of the third blended material may be decreased, increased, ordiscontinued relative to the first and second parallel systems. Anysuitable pattern and arrangement of any number of parallel systems,which may be varied by time, by composition, and by how they arearranged relative to each other, is envisioned by embodiments of thedisclosure.

In other embodiments, multiple systems may be operated in paralleland/or in series. For instance, in the example depicted above, the firstparallel system may blend materials that are themselves a blend ofmultiple materials and blended according to the embodiments of thedisclosure. That is, the first parallel system may blend one or morestreams of material that are each blended in a deposition head ordynamic mixing module according to the embodiments. There is nointention to limit the possible configurations of different shapes,properties, and arrangements.

In certain embodiments, the deposition apparatus 206 may producefilaments, points, or layers that are hollow or comprise apertures orother textures. In place of the inner layer of material provided by theimpeller 281, a single outer layer of material may be provided around aflange to produce a hollow interior that reduces the weight and bulk ofan additive manufactured article. Gaps, apertures, or other textures maylikewise be provided as suitable to vary any number of properties of thedeposited material or filament.

In another embodiment of an additive manufacturing system and componentsthereof shown in FIG. 9, a deposition apparatus 306 may receivematerials according to the previously described embodiments from firstand secondary dispensing mechanisms and/or displacement pumps. Thedeposition apparatus 306 is also equipped with a dynamic mixing module350 and a pneumatic stop valve 362 to allow for precise depositions ofmaterial from nozzle 390, as described previously. While the nozzle 390is shown as being arranged downwardly of the dynamic mixing module 350and pneumatic stop valve 362, it will be appreciated that the componentsof the deposition apparatus 306 may take any suitable configuration,shape, or order, as described in greater detail below.

In addition to the deposition apparatus 306, a deposition substrate 330is provided to enable dynamic depositions of material. The depositionsubstrate 330 may provide a movable substrate on which to deposit anarticle. This arrangement allows for multiple orders, layers, anddirections of additive construction, increasing the flexibility of theadditive manufacturing process. The deposition substrate 330 maycomprise in the depicted embodiment a rotating mandrel 336, which isconfigured to rotate in a direction R9 as the deposition apparatus 306deposits polymeric material on a surface thereof. As the rotatingmandrel 336 rotates in the direction R9, not only may the depositionapparatus 306 deposit material in different patterns and orders alongthe surface of the spinning rotating 336, but the rotating mandrel 336may also advantageously overcome the deleterious effects of gravity onthe additive manufacturing process.

It has been surprisingly found that as the rotating mandrel 336 rotatesin the direction R9, the counteraction of centripetal and centrifugalforces acting on the deposited material on the surface of the rotatingmandrel 336 prevents unwanted deformation of the article, especially ascomponents thereof grow in height, weight, or other dimensions and asthe material is being fully cured. The centripetal and centrifugalforces, operating oppositely in directions pointing inward toward thecenter of the rotating mandrel 336 and outwardly of the center of therotating mandrel 336, operate to prevent the growing article, formedfrom deposited material, from drooping laterally, collapsing, orotherwise changing its configuration as happens to ubiquitously inexisting 3D-printing systems that utilize a rotating build surface.While the rotating mandrel 336 is shown as having a conicalconfiguration, any other shape or configuration may be utilized.

By providing the rotating mandrel 336 in combination with the depositionhead 306, the problems of existing 3D-printing systems, including thosethat utilize rotating surfaces, requiring the use of cutters, shavers,and drip pans to catch falling material are avoided. Instead, theadditive manufacturing system of the disclosure can continuously depositelastomeric material in filaments, beads, or layers without the knownissues of drooping, deforming, or smearing.

A moving rack 332 is provided on which the rotating mandrel 336 ismounted via an attachment block 331. An actuator 334, such as a motor orother suitable device, provides the rotation R9 of the rotating mandrel336. The rotating mandrel 336 may thus advantageously translate alongwith the moving rack 332 by means of an actuator 335 to furtherfacilitate patterns and/or layers of deposited through the nozzle 390.In contrast to existing additive manufacturing devices limited toprinting only in cartesian coordinates, such as with an ink-jet printer,the additive manufacturing system of embodiments of the disclosure canprint in angular coordinates and in any order or pattern necessary. Forexample, the article deposited and formed on the rotating mandrel 336may be formed inside-out, with the article being reversed upon removalfrom the rotating mandrel 336. The article may also be formedright-side-out, with multiple layers being deposited in a woven fashion.

While in the depicted embodiment the rotating mandrel 336 is moved andtranslated relative to the nozzle 390 by means of the moving rack 332and the actuator 335, in embodiments the deposition apparatus 306 may beconfigured to move and translate relative to the mandrel 336. Both thedeposition apparatus 306 and the mandrel 336 may move relative to eachother as suitable for a particular application. As described above, theability to move one of the substrate or rotating mandrel 336 and thedeposition apparatus 306 relative to each other allows the nozzle 390 totravel along the surface of the rotating mandrel 336 while depositing acontinuous filament, bead, or layer of elastomeric material,facilitating an efficient, precise, and continuous build process.

The rotating mandrel 336 may accelerate the curing process of thedeposited material by providing a heat-transfer module 335, wherein heator refrigeration may be provided. For example, the heat-transfer module335 may comprise tubing that extends along an inner surface of therotating mandrel 336 to provide heat to the deposited material foraccelerated curing. Alternatively, the heat-transfer module 335 may beconfigured to provide cooling or refrigeration to the surface of therotating mandrel 336, delaying the curing process as additional layersor filaments of material are deposited, thus facilitating improvedbonding between distinct filaments, for example, as subsequentlydeposited filaments have more time to chemically bond with a previouslydeposited and as-yet uncured filament. In other embodiments, the heattransfer module may apply heating or cooling to a conductive surface ofthe rotating mandrel 336.

The heat-transfer module 335 may provide a dynamic heat-transfer profileover a surface of the rotating mandrel 336. Increased heat transfer maybe effected at discrete regions of the rotating mandrel 336. Forexample, the heat-transfer module 335 may utilize a heated fluidprovided by a pump or other actuator (now shown) to a channel near asurface of the rotating mandrel 336 as indicated by the controller toincrease a rate of curing of recently deposited material, while anothersurface of the mandrel 336 is provided with a lower flow rate of theheated fluid; this may help ensure that the material deposited there canbond to other subsequently deposited filaments.

In a variation, the deposition apparatus 306 may move in relation to thedeposition substrate 330, where both the deposition apparatus 306 andthe deposition substrate 330 may move in relation to the other, or bothmay move. The deposition substrate 330 may translate as a rotatingmandrel 336 and translate in a direction, such as along a horizontaldirection or plane in the depicted embodiments, according to the desiredarticle. In each instance, the deposition apparatus 306 is metered (andmoved, if so arranged), and the deposition substrate 330 is movableaccording to the CAM system controlling the manufacturing process.

The CAM system may be any suitable system for directing the operation ofthe first and second dispensing systems, the deposition apparatus, andthe deposition substrate according to embodiments of the disclosure. Acomputer numerical control (CNC) system may also be utilized inembodiments. A controller or control system can be arranged to receivesignals from a plurality of sensors arranged throughout the additivemanufacturing system. For instance, sensors may be arranged to detectflow rates of material, pressures, temperatures, positions, velocities,and orientations of particular components.

In embodiments, a sensor can detect the orientation of the depositionsubstrate relative to the nozzle of the deposition head. A sensor candetect an amount of material in one or more of the vats or reservoirs inthe first or primary dispensing system and/or an amount of materialaccumulated in the proportioning columns of the secondary dispensingsystem. At least one processor can be configured to direct the operationof the components of the additive manufacturing system, such as thecontrol valves 110A-D, 114A-D, the displacement pump 124, the dynamicmixing module, or the movement of the deposition substrate in rotationand translation, for example. The control system may utilize servocontrol of various actuators that control the control valves, pumps,deposition apparatus, impellers, pneumatic suck-back valves, and othermoving components of the additive manufacturing system to attain anadditively manufactured article with regions having different propertiesat desired locations. The servo control of the components may impart tothe system greater accuracy and angular repeatability over othermodalities, though the disclosure is not limited to servo control.

Each actuator of the additive manufacturing system that isservo-controlled can be individually and manually tuned to optimize theoperation of the system during the additive manufacturing of aparticular article. The operation of the servo-controlled actuators thatcontrol the dispensing systems, the deposition apparatus, and thedeposition substrate can be optimized and adjusted during use based on aprocess control scheme using a control loop. For example, PID(proportional-integral-derivative) control in any suitable variety suchas parallel, series, or expanded form, PI (proportional-integral)control, PD (proportional-derivative) control, proportional control,two-position control, feedback, feedforward, or model-predictivecontrol, combinations thereof, and/or any other suitable process controlscheme may be used to control the additive manufacturing system.

The controller may further comprise any suitable utility for convertingCAD files or other files into instructions for the additivemanufacturing system. The utility for converting CAD files or otherfiles into suitable instructions may account for different propertiesnecessary or desired at different locations along or throughout anadditively manufactured article, such as different colors, elasticities,durometers, etc. Based on the different properties desired, thecontroller may determine an appropriate blend of materials needed toachieve the desired properties and, based on a desired path that thedeposition apparatus may trace across a surface of the depositionsubstrate, an appropriate time for the determined blend of materials tobe fed forward the deposition apparatus, so the determined blend arrivesat the nozzle at the desired time and location.

The deposition apparatus 306 is shown in a cutaway elevational view ingreater detail in FIG. 11. As in previous embodiments, the dynamicmixing module 350 may comprise an impeller 380, comprising on an outersurface with protrusions arranged to blend two or more streams ofmaterial into a smooth, consistent blended material stream and to drivethe material toward the nozzle 390. A material control valve 370 mayadvantageously control the volume or flow rate of materials into thedynamic mixing module 350 and material may be conducted into the dynamicmixing module 350 via a material line 340. A pneumatic suck-back valve362 may operate similar to previous embodiments wherein a plunger 363may be withdrawn to create a negative pressure proximate the nozzle 390to draw blended material back into the deposition apparatus 306. Theoperation of the pneumatic suck-back valve 362 serves to mitigatesmearing and enable discrete deposits and discrete apertures with acontinuous layer or filaments.

The rotating mandrel 336 may be customized to a specific or desiredconfiguration for the final additive-manufactured article. For example,foam or other shapeable and/or additive material may be added onto anouter surface of the rotating mandrel 336 to create a substrate havingdynamic or customized dimensions on which the material may be deposited.In other embodiments, the rotating mandrel 336 may comprise or supportstructures to be integrated into the final article and around which thefinal article may be additive manufactured. For example, a stiffeningmatrix or a textile sleeve may be added to the rotating mandrel 336 andthe article additive manufactured thereon and/or therearound. Inembodiments, the structures are added to the rotating mandrel 336 and/orto the additively manufactured article during or after the depositionprocess.

In embodiments, an article may be additive manufactured on a planarsubstrate and then mounted on the rotating mandrel 336 for furtherdepositions. In an example, a textile material arranged to form an outerlayer of an elastomeric liner may be additively manufactured withcertain elastomeric structures such as seal-in bands or other frictionalfeatures on a planar surface. The textile material is then mounted ontothe rotating mandrel 336, after which a silicone liner may be additivelymanufactured by the system of the disclosure over the textile material.

Other combinations of pre-processing steps and pre-arranged materialsare likewise envisioned. Additionally, the additively manufacturedarticle may be post-processed in further steps; for instance, theadditively manufactured article may be removed from the rotating mandrel336 after the deposition process is complete and further additivemanufacturing steps may be performed on a rotating planar surface or anon-rotating build surface.

The configuration of the nozzle 390 may be dynamic and may change bymeans of an actuator during deposition to build up particular structuresor articles. In embodiments, the nozzle 390 may take a horizontalconfiguration relative to the rotating mandrel 336 near a base of thestructure being deposited on the rotating mandrel 336 and may transitionto a vertical configuration nearer a top surface of the structure beingdeposited on the rotating mandrel 336. In embodiments, the depositionapparatus 306 may be arranged to deposit material in a spiral patternaround the rotating mandrel 336, attaining a weaving pattern withdesired characteristics in terms of strength and elasticity whileminimizing the amount of material used. The actuator may also change aconfiguration of the nozzle shape, such that as a continuous filament isbeing deposited, a larger filament or different shape of filament may bedeposited at certain regions of the article without breaking continuityof the continuous filament. This allow for different properties to beimparted to the additively manufactured article at desired locations.

As seen from FIGS. 12A-12C, the deposition substrate such as a rotatingmandrel 336 may be provided with heat-transfer channels for cooling andfor heating. Cooling channels 438 may extend from a backside of therotating mandrel 436 and through a thickness of the rotating mandrel336. The cooling channels 438 may define a “v” shape corresponding to aconical shape of the rotating mandrel 436 and may join near a distal orfront end of the rotating mandrel 436. As such, one of the coolingchannels 438 can define an inlet, and another can define an outlet suchthat a current of cooling media is provided through the cooling channels438.

The cooling channels 438 may be connected with an attachment block asdescribed in foregoing embodiments in any suitable manner, and thecooling medium may be any suitable medium, such as cooling water,refrigerant, a gas, or any other suitable medium. The depictedembodiment and description of the cooling channels 438, as with thedepiction of the rotating mandrel as being conical in shape, is merelyexemplary, and any suitable configuration may be adopted.

For instance, in embodiments in which the substrate is a rotating planersurface, the cooling channels 438 may be defined through the thicknessof the planer surface in any suitable configuration. The coolingchannels 438 may have a symmetric or asymmetric configuration and mayprovide heat transfer in an even and consistent manner or may provideheat transfer in a dynamic manner and at desired locations. Also shownis an attachment 442 at which the rotating mandrel 436 can removablyattach to the attachment block by any suitable means. The removableattachment of the rotating mandrel 436 can facilitate the use ofdifferently shaped substrates in the additive manufacturing system forimproved customizability of the additively manufactured articles and foroperational flexibility.

Also shown are heating channels 440. As with the cooling channels 338,the heating channels 440 can be configured to provide heat to a surfaceof the rotating mandrel 336 in any suitable configuration. Inembodiments, the heating channels 440 can be configured to receivecartridge heating modules. The cartridge heating modules may becontrolled by the CAM system to ensure that a desired amount of heatyielding a desired surface temperature is provided, this serving inembodiments to expedite a curing process of the deposited material. Theheat provided by each of the cartridge heating modules may be dynamic inthat a region of the surface of the rotating mandrel 436 may be heatedto promote curing while heat is not applied to another region, forinstance to delay a curing process until a subsequent filament isdeposited. In other embodiments, the heating channels 440 can beconfigured to receive a heating medium, such as a heated fluid or to useembedded electrical heating elements.

Turning to FIG. 12C, a shield 450 may be provided to surround therotating mandrel 436. The shield 450 may be arranged with apertures orother means that facilitate currents 452 of heating fluid such as hotair to flow inward and contact a surface 437 of the rotating mandrel436. The currents 452 within the shield 450 may further expedite thecuring process. Alternatively, the currents 452 may have a temperaturelower than a temperature of the deposited material to delay the curingprocess until subsequent filaments, or layers can be deposited.

FIGS. 13A and 13B show an embodiment of a rotating nozzle 490 accordingto another embodiment of the disclosure. Because the substrate maydefine an asymmetrical shape, it can be desirable to provide anotheraxis of rotation at the deposition head according to embodiments of thedisclosure to ensure that the nozzle deposits material at an angle thatis normal to any given point on the surface of the substrate. In thecase of the rotating mandrel 436, the mandrel 436 due to itssubstantially conical configuration can define a profile or curvature460. To allow the nozzle 490 to deposit material at an angle D13 that isnormal to the profile 460, the nozzle 490 can be a rotating nozzle 490that extends away from the deposition head on an arm or shaft 494. Thenozzle 490 may be rotated about an axis A13 by an actuator 480, whichmay attach to the deposition head at an attachment 482 comprising a body481.

To accommodate the profile 460 without disruption, the depositionsubstrate 436 and/or the deposition apparatus may comprise an actuator(not shown) configured to change a vertical position of the depositionsubstrate 436 relative to the deposition apparatus. The actuator allowsthe nozzle 490 to contact the surface of the deposition substrate 436 ata desired distance suitable for depositing the elastomeric materialregardless of the profile 460, which may otherwise change a distance bywhich the deposition substrate 436 and the nozzle may be spaced apart.This may be particularly beneficial in instances when the depositionsubstrate 436 is asymmetric so as to define an asymmetric final articleshape.

The deposition apparatus may be further provided with curing means 470configured to expedite a curing process further. The curing means 470may be a UV lamp or a heat lamp. By providing the curing means 470 incombination with the deposition apparatus, deposition substrate, and thematerial blend as described herein, the additively manufactured productmay overcome the problems of existing processes which require cutters,shavers, and drip means to address the problem of deposited materialbeing imprecisely deposited and poorly cured in situ to define anarticle with precise features having desired properties.

By contrast, the additive manufacturing system of the disclosure, bycombining the use of a deposition apparatus provided with blends ofmaterials having tailored properties and a deposition substrateaccording to the embodiments, enables the deposition and additivemanufacturing of articles having tailored properties at desiredlocations while providing a cleaner and continuous process for additivemanufacturing of elastomeric articles.

FIGS. 14A-D show embodiments of a mounting mechanism 500, 600 configuredto cooperate with the deposition substrate. FIGS. 14A and 14B show amounting mechanism 500 according to a first embodiment and configured tocooperate with a rotating mandrel according to embodiments disclosedherein. The mounting mechanism 500 may comprise several arms 502 thatfunction as end effectors and are configured to arrange or place aseparate article, such as a non-3D-printed article, upon the depositionsubstrate so as to engage with the additively manufactured article.

The mounting mechanism 500 may be used when assembling devices thatutilize pre- or post-processing steps to combine an additivelymanufactured article and a separate article to form a device. Anexemplary device formed using a mounting mechanism according toembodiments is a liner in which a textile sleeve is applied to anadditively manufactured silicone structure, but the disclosure is notlimited to this embodiment.

The end effectors 502 can be arranged about the mounting mechanism 500to form an enclosure or circumference substantially about the depositionsubstrate with which the mounting mechanism 500 is configured tocooperate. The end effectors 502 are adjustable to accommodatedifferently sized deposition substrates and additively manufacturedarticles built thereon. The end effectors 502 can be rotated or pivotedabout at least a first joint 505 to extend the circumference defined bythe end effectors 502, allowing the mounting mechanism 500 to engagewith a larger deposition substrate.

The end effectors 502 can be supported relative to a central actuator507 by arms 509 that extend outwardly from the central actuator 507. Theend effectors 502 can further be configured to pivot about a secondjoint 511 to maintain a substantially parallel relationship between theend effectors 502 and the deposition substrate. The central actuator 507can be driven by at least one motor driver 504. Alternatively, the endeffectors 502 can each be actuated independently of each other to enablethe mounting mechanism 500 to engage with an asymmetrically oreccentrically shaped deposition substrate.

In use, a separate article such as a textile sleeve is positioned on endeffectors 502 to define a circumference relative to the depositionsubstrate. The mounting mechanism 500, and the end effectors 502 can beadjusted, so the textile sleeve conforms in size and shape to thedeposition substrate. The mounting mechanism 500 can be configured totranslate relative to the deposition substrate to position thedeposition substrate within a cavity or space defined between the endeffectors 502, so the textile sleeve surrounds and engages thedeposition substrate.

In a second embodiment shown in FIGS. 14C-D, a mounting mechanism 600likewise comprises end effectors 602 arranged to define a circumferenceor enclosure around a deposition substrate. The end effectors 602 maysupport cable actuators 606 that can be routed along a length of the endeffectors 602 by routing mechanisms 610, which may be pulleys, guides,or any other suitable routing mechanism. The cable actuators 606 can bejointly actuated by a central actuator or spool 608 or may be providedwith respective actuators.

The cable actuators 606 can serve to move a separate article, such as anon-3D-printed article including a textile sleeve, toward a distal endof the end effectors 602 for placing on the deposition substrate. Aswith the embodiment of FIGS. 14A-B, the mounting mechanism 600 may beactuated relative to the deposition substrate such that the separatearticle mounted on end effectors 602 can substantially surround thedeposition substrate, such that as the cable actuators 606 move theseparate article toward the distal ends of the end effectors 602, theseparate article can be engaged with and onto the deposition substrateand the article being or recently additively manufactured thereon.

The cable actuators 606 may operate to move the textile sleeve atdifferent speeds at different times to precisely orient the separatearticle on the deposition substrate in the desired configuration. In anembodiment, the separate article is a textile sleeve to be placed on anelastomeric liner additively manufactured upon the deposition substrate.By arranging the textile sleeve on the elastomeric liner using themounting mechanism 600, an automated, and therefore more precise,mounting operation is facilitated, as the imprecisions and risksassociated with manually mounting the separate article on the depositionsubstrate are avoided.

While a rotating mandrel having a conical shape has been shown anddescribed, the deposition substrate may have any suitable configurationbased on any desired final article to be additively manufactured. Thedeposition substrate may be substantially planar, cylindrical,rectilinear, or any other suitable shape. The deposition substrate neednot be symmetric and can define any suitable profile. The additivemanufacturing system according to the disclosure can be utilized toadditively manufacture any suitable article, including elastomericbreast implants, liners, medical implants such as tubing and seals,joint component replacements, surgical tools, and any other suitabledevice.

In embodiments where the additive manufacturing system is configured toproduce an elastomeric breast implant, the deposition substrate may beprovided with a shape and/or rotation configuration that corresponds toa desired shape of the elastomeric breast implant. Because elastomericbreast implants often comprise an upper portion and a lower portion thatcan define an outer shell inside of which an elastomeric gel, salinesolution, or other suitable material can be contained, the depositionsubstrate of the additive manufacturing system may be configured toadditively manufacture a continuous or substantially continuous outershell from elastomeric material such that the outer shell has desiredproperties at desired locations. For example, a lower portion arrangedto be implanted inwardly can have a greater rigidity or lower elasticitythan an upper portion arranged to be implanted outwardly of the lowerportion. The upper portion may be additively manufactured to have, forexample, greater elasticity in regions to attain a suitable shape thatmay be asymmetric.

Because elastomeric breast implants are often asymmetric, the depositionsubstrate can be arranged to move relative to the deposition apparatus,whether by rotation, translation, or otherwise, to define the asymmetricshape of the elastomeric breast implant. In embodiments, the depositionsubstrate can be a planar surface on which the lower portion of theouter shell is first deposited by the additive manufacturing system asthe planar deposition substrate rotates relative to the depositionapparatus.

The additive manufacturing system can be operated so as to impartdesired properties such as durometer, elasticity, and other propertiesat desired points along the lower portion. The deposition apparatus maydeposit continuous filaments that have varying properties along a lengthof the continuous filament and which may chemically bond with adjacentand/or subsequently deposited filaments to define a continuouselastomeric body with desired properties at desired locations.

An upper portion can be built from and on the lower portion to define acontinuous outer shell and may comprise filaments that are continuouswith filaments that define the lower portion, while nevertheless havingdifferent properties to define the upper portion. The filaments may beinterspersed with continuously deposited layers and/or drops of anelastomeric material such that the outer shell may define any suitabletexture; for example, in embodiments the outer shell may comprise atextured outer surface comprising ridges and corresponding valleys. Inother embodiments, outer surfaces of the outer shell may besubstantially smooth. A dynamic texture and properties may be definedthrough a thickness of the outer shell, with a smooth and rigid innersurface of the outer shell configured to encase the silicone gel orsaline inside the implant, and with a textured outer surface configuredto disrupt capsular tissue after the implant has been placed. Thedescribed embodiment is merely exemplary and is not limiting.

In embodiments, the deposition substrate may be an additivelymanufactured article with dimensions corresponding to the customdimensions of an article to be printed thereon. For instance, inembodiments wherein the additive manufacturing system is utilized tocreate an elastomeric liner for a limb residuum, a user's limbdimensions can be measured and used to additively manufacture orotherwise prepare the deposition substrate to match the user's limb. Theadditively manufactured elastomeric liner can then correspond closely tothe user's limb.

By providing an additive manufacturing system, method, and correspondingcomponents for making elastomeric structures according to thedisclosure, the limitations of existing additive manufacturingmethods—namely, using low quality polymeric materials to facilitatebetter deposition, the effects of gravity distorting a manufacturedarticle, or the monolithic structure of the article, with a singlematerial having a single set of properties forming the entirestructure—are addressed. The additive manufacturing system provides adynamic system for selecting from infinitely many combinations ofmaterials and properties to create manufactured articles with dynamicproperties at desired regions within the printed article. The depositionapparatus provides for the creation of smooth and consistently blendedmaterials for reliable and consistent properties at desired regions. Thesystem may be arranged for co-extrusion of multiple layers of materialshaving different properties. A deposition substrate may advantageouslyprovide a dynamic surface on which to build an additive manufacturedarticle.

It is to be understood that not necessarily all objects or advantagesmay be achieved under an embodiment of the disclosure. Those skilled inthe art will recognize that the additive manufacturing system, method,and corresponding components for making elastomeric structures may beembodied or carried out in a manner that achieves or optimizes oneadvantage or group of advantages as taught herein without necessarilyachieving other objects or advantages as may be taught or suggestedherein.

The skilled artisan will recognize the interchangeability of variousdisclosed features. In addition to the variations described herein,other known equivalents for each feature can be mixed and matched by oneof skill in this art to construct an additive manufacturing system,method, and corresponding components for making elastomeric structuresin accordance with principles of the present disclosure. It will beunderstood by the skilled artisan that the features described herein mayapply to other types of additive manufacturing systems, materials, andarticles.

Although this disclosure describes certain exemplary embodiments andexamples of an additive manufacturing system, method, and correspondingcomponents for making elastomeric structures, it nevertheless will beunderstood by those skilled in the art that the present disclosureextends beyond the specifically disclosed embodiments to otheralternative embodiments and/or users of the disclosure and obviousmodifications and equivalents thereof. It is intended that the scope ofthe present disclosure should not be limited by the particular disclosedembodiments described above and may be extended to other additivemanufacturing systems and methods, and other applications that mayemploy the features described herein.

1. A system for additive manufacturing, comprising: a first dispensingsystem comprising a reservoir of at least one elastomeric material; asecondary dispensing system comprising at least one proportioning deviceand at least one control valve, the secondary dispensing systemconfigured to receive the at least one elastomeric material from thefirst dispensing system in predetermined quantities; and a depositionapparatus arranged to mix the at least one material from the seconddispensing system prior to depositing the at least one elastomericmaterial; a deposition substrate on which the at least one elastomericmaterial is deposited, said deposition substrate arranged to move as thedeposition apparatus deposits the at least one elastomeric material;wherein the deposition apparatus or the deposition substrate translatesin a different direction to the first direction as the depositionapparatus deposits the at least one elastomeric material onto thedeposition substrate.
 2. The system for additive manufacturing of claim1, wherein the deposition apparatus comprises a sonic vibration module.3. The system for additive manufacturing of claim 1, wherein thedeposition apparatus comprises a nozzle, a dynamic mixer, and a secondcontrol valve, the dynamic mixer configured to mix the at least onematerial from the second dispensing system prior to depositing the atleast one elastomeric material.
 4. The system for additive manufacturingof claim 3, wherein the deposition apparatus further comprises at leastone heating and/or cooling element.
 5. The system for additivemanufacturing of claim 3, wherein the deposition apparatus furthercomprises at least one pneumatic suck-back valve.
 6. The system foradditive manufacturing of claim 3, wherein the dynamic mixer comprisesan impeller arranged to rotate and actuated by a driver.
 7. The systemfor additive manufacturing of claim 3, wherein the deposition apparatuscomprises a sonic vibration module proximate the nozzle.
 8. The systemfor additive manufacturing of claim 3, wherein the deposition apparatuscomprises at least one temperature sensor and at least one pressuresensor.
 9. The system for additive manufacturing of claim 3, wherein theat least one proportioning device, the at least one control valve of thesecondary dispensing system, the dynamic mixer, and the depositionsubstrate are servo controlled.
 10. The system for additivemanufacturing of claim 3, wherein a plurality of elastomeric materialsand a plurality of proportioning devices and corresponding controlvalves are provided in the secondary dispensing system, a proportioningdevice and control valve pair corresponding to a respective materialarranged to be drawn from the primary dispensing system.
 11. The systemfor additive manufacturing of claim 1, wherein a displacement unit ofthe secondary dispensing system is configured to receive and dispensethe at least one elastomeric material to the deposition apparatus in anorder in which the at least one elastomeric material was received in thedisplacement unit.
 12. The system for additive manufacturing of claim 1,wherein parallel deposition apparatuses are arranged to provide fordeposition of different blends of the at least one elastomeric material.13. The system for additive manufacturing of claim 12, wherein theparallel deposition apparatuses comprise a shared nozzle arranged toreceive mixed different blends of elastomeric material from the paralleldeposition apparatuses and to deposit the different blends of materialin an adjacent, concentric, or otherwise engaged configuration.
 14. Thesystem for additive manufacturing of claim 1, wherein the depositionapparatus is arranged with a hollow nozzle configured to deposit the atleast one elastomeric material in a hollow filament configuration. 15.The system for additive manufacturing of claim 1, wherein the depositionsubstrate is a cylindrical or conical mandrel.
 16. The system foradditive manufacturing of claim 1, wherein the deposition substraterotates as the deposition apparatus deposits the at least oneelastomeric material.
 17. The system for additive manufacturing of claim1, wherein the deposition substrate comprises heating and/or coolingelements.
 18. A system for additive manufacturing, comprising: a firstdispensing system comprising a reservoir of at least one elastomericmaterial; a secondary dispensing system comprising at least oneproportioning device and at least one control valve, the secondarydispensing system configured to receive the at least one elastomericmaterial from the first dispensing system in predetermined quantities; adeposition apparatus configured to receive and mix the at least onematerial from the second dispensing system prior to depositing the atleast one elastomeric material; a deposition substrate configured totranslate relative to the deposition apparatus and to rotate in a firstdirection; and a controller configured to operate the first and seconddispensing systems, the deposition apparatus, and the depositionsubstrate using servo control; wherein the deposition substratecomprises heating and/or cooling elements.
 19. The system for additivemanufacturing of claim 18, wherein the deposition apparatus comprises asonic vibration module.
 20. A system for additive manufacturing,comprising: a first dispensing system comprising a reservoir of at leastone elastomeric material; a secondary dispensing system comprising atleast one proportioning device and at least one control valve, thesecondary dispensing system configured to receive the at least oneelastomeric material from the first dispensing system in predeterminedquantities; a deposition apparatus configured to receive and mix the atleast one material from the second dispensing system prior to depositingthe at least one elastomeric material, the deposition apparatus furthercomprising a sonic vibration module; a deposition substrate having asubstantially cylindrical shape and configured to translate relative tothe deposition apparatus and to rotate in a first direction; and acontroller configured to operate the first and second dispensingsystems, the deposition apparatus, and the deposition substrate usingservo control; the additive manufacturing system arranged to depositcontinuous filaments of the at least one elastomeric material on asurface of the deposition substrate with controlled variation ofproperties of the at least one elastomeric material through a length ofthe continuous filaments.